refactor: use ALS for process.env object

.changeset/funny-impalas-attend.md

@@ -0,0 +1,7 @@
+---
+"@opennextjs/cloudflare": patch
+---
+
+refactor: use ALS for `process.env` object.
+
+The adaptor was previously manipulating the global process.env object on every request, without accounting for other requests. ALS has been introduced to change this behavior, so that each process.env object is scoped to the request.

packages/cloudflare/src/cli/templates/utils/create-als-proxy.ts

@@ -0,0 +1,18 @@
+import type { AsyncLocalStorage } from "node:async_hooks";
+
+/**
+ * Creates a proxy that exposes values from an AsyncLocalStorage store
+ *
+ * @param als AsyncLocalStorage instance
+ */
+export function createALSProxy<T>(als: AsyncLocalStorage<T>) {
+  return new Proxy(
+    {},
+    {
+      ownKeys: () => Reflect.ownKeys(als.getStore()!),
+      getOwnPropertyDescriptor: (_, ...args) => Reflect.getOwnPropertyDescriptor(als.getStore()!, ...args),
+      get: (_, property) => Reflect.get(als.getStore()!, property),
+      set: (_, property, value) => Reflect.set(als.getStore()!, property, value),
+    }
+  );
+}

packages/cloudflare/src/cli/templates/utils/index.ts

@@ -0,0 +1 @@
+export * from "./create-als-proxy";

packages/cloudflare/src/cli/templates/worker.ts

@@ -9,23 +9,20 @@ import { MockedResponse } from "next/dist/server/lib/mock-request";
 import type { NodeRequestHandler } from "next/dist/server/next-server";
 
 import type { CloudflareContext } from "../../api";
+import { createALSProxy } from "./utils";
 
 const NON_BODY_RESPONSES = new Set([101, 204, 205, 304]);
 
+const processEnvALS = new AsyncLocalStorage<Record<string, unknown>>();
 const cloudflareContextALS = new AsyncLocalStorage<CloudflareContext>();
 
 // Note: this symbol needs to be kept in sync with the one defined in `src/api/get-cloudflare-context.ts`
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
-(globalThis as any)[Symbol.for("__cloudflare-context__")] = new Proxy(
-  {},
-  {
-    ownKeys: () => Reflect.ownKeys(cloudflareContextALS.getStore()!),
-    getOwnPropertyDescriptor: (_, ...args) =>
-      Reflect.getOwnPropertyDescriptor(cloudflareContextALS.getStore()!, ...args),
-    get: (_, property) => Reflect.get(cloudflareContextALS.getStore()!, property),
-    set: (_, property, value) => Reflect.set(cloudflareContextALS.getStore()!, property, value),
-  }
-);
+(globalThis as any)[Symbol.for("__cloudflare-context__")] = createALSProxy(cloudflareContextALS);
+
+const originalEnv: Partial<typeof process.env> = { ...globalThis.process.env };
+// @ts-expect-error - populated when we run inside the ALS context
+globalThis.process.env = createALSProxy(processEnvALS);
 
 // Injected at build time
 const nextConfig: NextConfig = JSON.parse(process.env.__NEXT_PRIVATE_STANDALONE_CONFIG ?? "{}");
@@ -34,40 +31,41 @@ let requestHandler: NodeRequestHandler | null = null;
 
 export default {
   async fetch(request, env, ctx) {
-    return cloudflareContextALS.run({ env, ctx, cf: request.cf }, async () => {
-      if (requestHandler == null) {
-        globalThis.process.env = { ...globalThis.process.env, ...env };
-        // Note: "next/dist/server/next-server" is a cjs module so we have to `require` it not to confuse esbuild
-        //       (since esbuild can run in projects with different module resolutions)
-        // eslint-disable-next-line @typescript-eslint/no-require-imports
-        const NextNodeServer = require("next/dist/server/next-server")
-          .default as typeof import("next/dist/server/next-server").default;
-
-        requestHandler = new NextNodeServer({
-          conf: nextConfig,
-          customServer: false,
-          dev: false,
-          dir: "",
-          minimalMode: false,
-        }).getRequestHandler();
-      }
+    return processEnvALS.run({ NODE_ENV: "production", ...originalEnv, ...env }, () => {
+      return cloudflareContextALS.run({ env, ctx, cf: request.cf }, async () => {
+        if (requestHandler == null) {
+          // Note: "next/dist/server/next-server" is a cjs module so we have to `require` it not to confuse esbuild
+          //       (since esbuild can run in projects with different module resolutions)
+          // eslint-disable-next-line @typescript-eslint/no-require-imports
+          const NextNodeServer = require("next/dist/server/next-server")
+            .default as typeof import("next/dist/server/next-server").default;
+
+          requestHandler = new NextNodeServer({
+            conf: nextConfig,
+            customServer: false,
+            dev: false,
+            dir: "",
+            minimalMode: false,
+          }).getRequestHandler();
+        }
 
-      const url = new URL(request.url);
+        const url = new URL(request.url);
 
-      if (url.pathname === "/_next/image") {
-        const imageUrl =
-          url.searchParams.get("url") ?? "https://developers.cloudflare.com/_astro/logo.BU9hiExz.svg";
-        if (imageUrl.startsWith("/")) {
-          return env.ASSETS.fetch(new URL(imageUrl, request.url));
+        if (url.pathname === "/_next/image") {
+          const imageUrl =
+            url.searchParams.get("url") ?? "https://developers.cloudflare.com/_astro/logo.BU9hiExz.svg";
+          if (imageUrl.startsWith("/")) {
+            return env.ASSETS.fetch(new URL(imageUrl, request.url));
+          }
+          return fetch(imageUrl, { cf: { cacheEverything: true } });
         }
-        return fetch(imageUrl, { cf: { cacheEverything: true } });
-      }
 
-      const { req, res, webResponse } = getWrappedStreams(request, ctx);
+        const { req, res, webResponse } = getWrappedStreams(request, ctx);
 
-      ctx.waitUntil(Promise.resolve(requestHandler(new NodeNextRequest(req), new NodeNextResponse(res))));
+        ctx.waitUntil(Promise.resolve(requestHandler(new NodeNextRequest(req), new NodeNextResponse(res))));
 
-      return await webResponse();
+        return await webResponse();
+      });
     });
   },
 } as ExportedHandler<{ ASSETS: Fetcher }>;